Today's vehicles are often equipped with an engine fan adapted inter alia to cool the engine. A type of engine fan is connected to and driven by a crankshaft of the engine. Such a fan has a dual function. Its first function is to create a flow of surrounding air which externally cools the engine and components associated with the engine, e.g. electronic components. The second function of the fan is to create an increased air flow through a vehicle cooler by an induction effect or a positive pressure effect, depending on which side of the radiator the fan is situated, thereby improving the cooling of a cooling medium which flows through the vehicle cooler and is intended to cool the engine from inside.
The engine fan is currently controlled electronically by a control unit of the vehicle. The control of the engine fan is currently on the basis of a number of parameters, e.g. the temperature of the cooling medium. As it is driven by the vehicle's engine, it is desirable for the engine fan to be controlled in such a way as to keep fuel consumption as low as possible. If the engine fan is controlled in a way which reduces the amount of fuel needed, there is also a reduction in fan noise, which is advantageous from a work environment perspective for a driver and the surroundings.
However, both the engine and components associated with it will be at a higher average temperature when their cooling is limited in this way. This has undesirable effects in that the service life of the engine and associated components may be shortened. A higher average temperature often contributes to greater wear of such equipment. The cooling system as such may also be subject to more severe wear in conditions which involve higher mean temperatures and more and higher temperature peaks. In situations where the temperature of said cooling medium exceeds a certain temperature, it is also necessary to reduce the engine's power output in order to prevent acutely damaging effects on, for example, the engine, electronic components and the cooling system. This downward adjustment of the engine's power output may be viewed unfavourably by a driver, particularly in situations which normally call for high performance of the vehicle, e.g. when a heavily laden vehicle travels uphill.
In the light of the above, it is currently important to find a compromise for controlling the engine fan in such a way as to achieve a balance between saving fuel on running the fan and increasing the cooling of, for example, the engine and associated electronics in order to reduce their wear.
Static regulation of the fan is current practice, which means that regulating the fan depends on predetermined parameters and limit values of them, and on fan speeds. Limit values for various parameters are adjusted to maintain a balance between fan noise, component wear and fuel consumption. There is therefore a need to improve the performance of today's motor vehicles.
US 20070006826 describes a propulsion system and method for optimisation of energy supply to a cooling system thereof.